Michael Bloomberg, against climate change and anti-Trump

Former New York mayor Michael Bloomberg is using his vast fortune, estimated at $51 billion, to spur action to address climate change -- and to tilt the US Congress toward Democratic control.

The 76-year-old businessman, activist, philanthropist and potential presidential aspirant spoke with AFP on the sidelines of the One Planet Summit featuring several world leaders Wednesday in New York City.

When he took the podium he reiterated the message he delivered at a climate conference he co-organized in San Francisco two weeks ago; that private initiatives and local actors could take over from states when it comes to meeting the challenges of global warming.

QUESTION: Why do you present yourself as an eternal optimist on climate, given how many leaders warn that the Earth is careening toward disaster?

BLOOMBERG: "We are making progress, China is making some progress, throughout Europe they're making some progress. In the end, it's not governments that drive behavior, it's capitalism, it's the economic interest of companies who want to be environmentally friendly because their employees want it, their investors want it, their customers want it. And individuals who want to breathe clean air today and drink clean water today.

"Basically, the federal government has been missing in action for a long time, not just this administration. But it really doesn't matter because coal fired power plants, no matter what the government says, are going to go out of business because of low-priced natural gas.

"So the federal government can make things worse with some environmental rules and rolling back some of our things, but the good news is in America, the courts are stopping our government from rolling most of them back."

QUESTION: Isn't China still building coal-fired plants?

BLOOMBERG: "It's still opening coal plants, but it's also closing a bunch... India is even worse.

"And eventually I think China will come around to understand that because of their geography, they're going to run out of water unless we do something here. Because of their geography, and the number of poor people who can't have filters in their air and live in closed houses, they are going to really suffer."

QUESTION: You have said you are actively considering a White House run in 2020. What is your deadline for deciding?

BLOOMBERG: "There's no deadline. I think it's probably not right after the (midterm elections set for November 6) -- within the next two or three months after that you would have to start focusing. But there's no drop dead date we have to do it.

"It'd be harder to do it the day before the election, it'd be a little bit easier two days before, and a year and a half before it would be much easier."

QUESTION: You also announced a few months ago that you would spend $80 million supporting Democratic congressional candidates in the November elections. Where are you on that?

BLOOMBERG: "There are some people who are running for Congress, women and men, a lot more women than men this time, who will all of a sudden see ads on television that are helpful to them or hurtful, depending on which side they're on.

"But we're not going to help people that have no chance whatsoever, nor people that have a very good chance and don't need our help. It's in the middle, it will be 25, some number like that.

"I think we'll do more than 80 (million dollars)... I think I have an obligation to do that. I can afford to do it, and I should do everything I can to improve the government that I'm going to leave to my children and grandchildren."